document.write( "Question 130889: 3x-y=7 10x-5y=25 solve by elimination,substitution,& graphing
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Algebra.Com's Answer #254779 by Fombitz(32388) $\"\"$ $\"About$

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1. $\"3x-y=7\"$
\n" ); document.write( "2. $\"10x-5y=25\"$
\n" ); document.write( "Multiply eq. 1 by (-5) and add the equations together to eliminate y and solve for x.
\n" ); document.write( " $\"-15x%2B5y%2B10x-5y=-35%2B25\"$
\n" ); document.write( " $\"-5x=-10\"$
\n" ); document.write( " $\"x=2\"$
\n" ); document.write( "Then use either equation to solve for y.
\n" ); document.write( " $\"3%282%29-y=7\"$
\n" ); document.write( " $\"6-y=7\"$
\n" ); document.write( " $\"y=-1\"$
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\n" ); document.write( "1. $\"3x-y=7\"$
\n" ); document.write( "2. $\"10x-5y=25\"$
\n" ); document.write( "From eq. 1,
\n" ); document.write( " $\"y=3x-7\"$
\n" ); document.write( "Substitute into eq. 2,
\n" ); document.write( " $\"10x-5%283x-7%29=25\"$
\n" ); document.write( " $\"10x-15x%2B35=25\"$
\n" ); document.write( " $\"-5x=-10\"$
\n" ); document.write( " $\"x=2\"$
\n" ); document.write( "Then,
\n" ); document.write( " $\"y=3%282%29-7\"$
\n" ); document.write( " $\"y=-1\"$
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